A new mandarin cultivar Citrus reticulata hybrid is described. The new variety named xe2x80x98Noraxe2x80x99 is desirable to the consumer because of the orange-red appearance of the fruit, and pleasant aroma of the juice and to commercial growers because of its zero to maximum six seeds per fruit and late ripening season (February to beginning of March).
The present invention relates to a new and distinct variety of mandarin tree of the new cultivar Citrus reticulata hybrid developed by inventors Aliza Vardi, Pinchas Spiegel-Roy, Avraham Elchanati, Ahuva Frydman-Shani and Hana Neumann in Bet Dagan, Israel from a selection of plants grown from irradiated bud wood of the cultivar xe2x80x98Noritxe2x80x99 (unpatented).
Asexual reproduction by conventional grafting methods of the new variety in Israel by grafting has shown that the new characteristics are stabilized and permanently fixed through successive propagation.
The objective in breeding the present new tree variety, assigned the denomination xe2x80x98Noraxe2x80x99, was to obtain late ripening mandarin citrus with few or no seeds. In the spring of 1989 about 400 buds of an easy peeling mandarin cultivar, xe2x80x98Noritxe2x80x99, were irradiated at the Weizmann Institute of Science, Rehovot, Israel, by exposure to 3.5 kh of gamma radiation from a Co60 source (G.B. 150A, Atomic Energy of Canada). Troyer nucellar rootstocks were bud grafted with the individual buds of irradiated xe2x80x98Noritxe2x80x99 bud wood and labeled mV1. Six to nine months after grafting the irradiated budwood, individual buds from the mV1 plants were regrafted on Troyer nucellar rootstocks to establish about 500 mV2 plants.
Field planting was established from container grown mV2 plants in the spring of 1991 and again in 1993. The first fruits were observed in January-March 1994 and the second observation in January-March 1995.
One of the selections, designated 8/260/52, had medium size orange-red color fruit and was easy to peel. The selection was distinguished from xe2x80x98Noritxe2x80x99 by having 0-6 seeds per fruit compared with 13-25 for xe2x80x98Noritxe2x80x99 and having flowers with low pollen fertility, typically 14.5% stained with acetocarmine compared with 87% staining for xe2x80x98Noritxe2x80x99.
Some of the characteristics of the new citrus, designated xe2x80x98Noraxe2x80x99 were compared with the parent xe2x80x98Noritxe2x80x99, as shown in Table 1.
The following is a detailed description of the new mandarin citrus variety based on observations made under typical Israeli grove conditions.
The tree shape and fruit appearance is similar to that of xe2x80x98Noritxe2x80x99. The tree is medium in size. Small thorns, 1 mm to 3 mm are usually present in the leafy part of branches, especially in their lower portion and on the lower part of fruit bearing branches. Main branches have an upright attitude and young shoots have no anthocyanin coloration at the tip.
The bearing of the tree is regular and the productivity is relatively high, about the same as for xe2x80x98Noritxe2x80x99. The canopy is moderately dense. The bark of the young shoots is initially smooth and green gradually turning into a smooth greyed-green.
The leaves are similar to that of xe2x80x98Noritxe2x80x99. They are lanceolate, small to medium in size. Leaf blade is firm, without undulation and slightly concave in cross section. petiols are without wings.
The characteristics of the flowering and the flower parts are similar to those of xe2x80x98Noritxe2x80x99. Flowering for both occurs at the end of March or first half of April as measured in Bet Dagan. Both xe2x80x98Noraxe2x80x99 and xe2x80x98Noritxe2x80x99 produce about the same number of flowers and flower drop for both occurs in April. Terminal flower buds have no anthocyanin coloration. Flowers are borne singly and have an average number of stamens (about 20) with complete style development. Anther color is pale yellow. Pollen fertility is low as indicated by the observation that only 14.5% of the pollen grains were stained with acetocarmine in a test conducted at the Agricultural Research Organization, the Volcani Center, as compared with stainability of about 87% for xe2x80x98Noritxe2x80x99 pollen grain.
The fruit has few seeds, about 0 to 6 seeds, even when optimal pollination conditions are employed. This compares with about 13 to 25 seeds per fruit in xe2x80x98Noritxe2x80x99. In other respects the fruit characteristics are in the range of the parent cv. xe2x80x98Noritxe2x80x99. The fruit has an oblate and slightly flattened shape and is medium sized. When 50 fruits were measured, the fruit had an average weight 145.5 grams, an average height 55.4 mm, and an average diameter 72 mm The fruit has a moderately depressed stalk end. The fruit surface is usually smooth with an orange-red color, 32B on The Royal Horticultural Society of London Colour Chart, and bears an average number of conspicuous rind oil glands. Fruit ripening does not differ from outside of the canopy to the inside, but the fruit color of the outside canopy are a little brighter compared to the fruit color of the inside canopy. There is no persistence of the style and the areola is not completely developed. A navel is absent or very rare. The rind is thin and easy to peel.
The color of the albedo is white and the flesh is orange in color. The fruit contains 11-13 segments and is very juicy. The external color of the seeds (when fresh) and dry is yellowish. The internal seed coat is white and the cotyledons are greenish.
Monoembryonic seeds are present. The seed sizes, shape and texture are similar to that of the parent xe2x80x98Noritxe2x80x99. The fruit reaches maturity late in the season as does xe2x80x98Noritxe2x80x99, which in Israel was mid-January to March. The ripening of the fruit on the tree and within the fruit is uniform. Fruit remaining on the tree does not regreen and does not begin to lose quality until end of February. If there is a heavy crop and the fruits are not picked before March it may becomes an alternate bearing (lighter crop the following season). Pre-harvest drop of both developed and undeveloped fruit is similar to that of the parent cv. xe2x80x98Noritxe2x80x99. The juice has a very pleasant aroma and flavor.